The present invention is directed to an inflation device, in the form of a syringe assembly, for pressurization and depressurization of a balloon catheter.
The General type of pressurization device is typified by prior U.S. Pat. No. 4,832,692, May 23, 1989 to Box et al. In such a device, a moveable piston is provided for initial pressurization of the fluid in communication with the balloon catheter. The final pressurization is achieved by threaded engagement between a half nut and a rod supporting the piston so that rotation of the rod will advance the piston and the piston will gradually increase the pressure in a precisely controlled amount. To release the pressure, the half nut is moved radially away from the threaded rod.
The present invention is directed to an improved system for controlling the positioning and release of the half nut which operates in conjunction with the threaded piston. A principal objective is to provide a very simple system which can be operated by one hand, which can't be inadvertently released and which is very simple to manipulate both for pressurization and release. This system is inexpensive and provides positive motion of the threaded component in both the engagement and release directions. Other patents of general background interest to the present invention are the following:
______________________________________ 4,583,974 Kokernak April 22, 1986 4,654,027 Dragan et al. March 31, 1987 2,475,939 Applezweig July 12, 1949 4,919,121 Rydell April 24, 1990 ______________________________________